Kaprekar constant 6174 JavaScript

var num = 4455, n1, n2, i = 0; for (i; num > 999 && num < 10000 && num !== 6174; i++) { n1 = +(("" + num).split("").sort((a, b) => a - b).join("")) n2 = +(("" + num).split("").sort((a, b) => b - a).join("")) num = n2 - n1; console.log(n2, "-", n1, "=", num); } console.log(i, "steps") 

var num = 4455; var arr, arr1, arr2; var n1, n2, result; var i; for (i = 0; num !== 6174 && num > 999 && num < 10000; i++) { arr = ("" + num).split("") arr1 = [...arr].sort((a, b) => a - b) arr2 = [...arr].sort((a, b) => b - a) //console.log(arr1); //console.log(arr2); n1 = Number(arr1.join("")) n2 = Number(arr2.join("")) result = n2 - n1; num = result; console.log(n2, "-", n1, "=", result); } console.log(i, "steps");